cluster: resolve relative unix socket paths

Relative unix sockets paths were previously interpreted relative
to the master's CWD, which was inconsistent with non-cluster behavior.
A test case has been added as well.

PR-URL: https://github.com/nodejs/node/pull/16749
Fixes: https://github.com/nodejs/node/issues/16387
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/test/parallel/test-cluster-net-listen-relative-path.js b/test/parallel/test-cluster-net-listen-relative-path.js
new file mode 100644
index 0000000000..0fcc6a0dca
--- /dev/null
+++ b/test/parallel/test-cluster-net-listen-relative-path.js
@@ -0,0 +1,44 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const cluster = require('cluster');
+const net = require('net');
+const path = require('path');
+const fs = require('fs');
+
+if (common.isWindows)
+  common.skip('On Windows named pipes live in their own ' +
+              'filesystem and don\'t have a ~100 byte limit');
+
+// Choose a socket name such that the absolute path would exceed 100 bytes.
+const socketDir = './unix-socket-dir';
+const socketName = 'A'.repeat(100 - socketDir.length - 1);
+
+// Make sure we're not in a weird environment
+assert.strictEqual(path.resolve(socketDir, socketName).length > 100, true,
+                   'absolute socket path should be longer than 100 bytes');
+
+if (cluster.isMaster) {
+  // ensure that the worker exits peacefully
+  process.chdir(common.tmpDir);
+  fs.mkdirSync(socketDir);
+  cluster.fork().on('exit', common.mustCall(function(statusCode) {
+    assert.strictEqual(statusCode, 0);
+
+    assert.strictEqual(
+      fs.existsSync(path.join(socketDir, socketName)), false,
+      'Socket should be removed when the worker exits');
+  }));
+} else {
+  process.chdir(socketDir);
+
+  const server = net.createServer(common.mustNotCall());
+
+  server.listen(socketName, common.mustCall(function() {
+    assert.strictEqual(
+      fs.existsSync(socketName), true,
+      'Socket created in CWD');
+
+    process.disconnect();
+  }));
+}